In the right triangle shown, $BC = 5$ and $AB = 8$. What is $AC$ ? $A$ $C$ $B$ $?$ $5$ $8$
Explanation: We know $a^2 + b^2 = c^2$ We want to find $b$ ; let $a = 5$ and $c = 8$ So $b^2 = c^2 - a^2 = 8^2 - 5^2 = 39$ Then, $b = \sqrt{39}$.